How to implement delegate in QHeaderView

I have created one table by using QTableview and QAbstractTableModel . i have added some vertical header by using QHeaderView . In one of the header cell i want to use delegate ..

I am using the delegate but it does not have any impact ..

Is anywhere i am doing wrong ?

Docs say

Quote:

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Note: Each header renders the data for each section itself, and does not rely on a delegate. As a result, calling a header's setItemDelegate() function will have no effect.

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Appearance.